Throttling issue

In the past, every once in a while I’d see where I was getting throttled and looking at the mysql_slow_queries files would try and determine what was causing it. Eventually got rid of my Coppermine photo album, did away with the calendar feature of my blog and also shut down the “search” feature on the blog.

However, it would still throttle for unexplained reasons.

The last few days it got really bad (throttling like 7,000 seconds in a 24 hour period.)

I got Supercache, installed it and activated it. I disabled all but the Akismet and Supercache plugins. Only have 8 left (All in one SEO pack, filosofo comments preview, SABRE, quotes collection, subscribe to comments, WordPress stats, W-P DB backup and WP ban.)

Since disabling the plug-ins and enabling Super-Cache,(over 12 hours ago) I have really not noticed much of an improvement, averaging about 300 seconds per hour. For one or two hours there will be virtually no throttling then all of a sudden 400-750 seconds per hour.

As an aside, in between the period when the throttling was somewhat under control and until just a few days ago, I’ve added no plug-ins or modified other features other than 1. disabling the “search” plugin a few days ago and the normal WP update a few hours after it came out some weeks ago.

What I find most of are these kinds of queries: (something to do with “month” and “year”)
# Query_time: 1.172817 Lock_time: 0.001317 Rows_sent: 20 Rows_examined: 14187
SELECT SQL_CALC_FOUND_ROWS wp_posts.* FROM wp_posts WHERE 1=1 AND YEAR(wp_posts.post_date)=2008 AND MONTH(wp_posts.post_date)=09 AND wp_posts.post_type = ‘post’ AND (wp_posts.post_status = ‘publish’) ORDER BY wp_posts.post_date DESC LIMIT 0, 20

Does anyone have any idea what is going on? What generates them?

Thanks!